Device with light-guiding layer

ABSTRACT

Devices ( 1 ) comprising light detectors ( 11 - 14 ) for detecting light and in response generating detection information, and light-guiding layers ( 15 ) comprising outer sides for guiding incident light ( 21 ) arriving at the outer sides and originating from input devices ( 20 ) towards the light detectors ( 11 - 14 ) are provided with converters ( 16 ) for converting the detection information into further information for taking into account one or more angles between the incident light ( 21 ) and an axis perpendicular to the light-guiding layer ( 15 ). As a result, one/two-dimensional corrections of locations of incidence can be made, and one/two-dimensional estimations of directions of user locations can be made, to adapt device parameters such as rotation, zooming, scrolling, volume, contrast, brightness or sound optimizing parameters, or to select a user from a plurality of users operating their own input devices ( 20 ). The devices ( 1 ) may further comprise displays ( 2 ), with the light-guiding layers ( 15 ) comprising inner sides for guiding light arriving at the inner sides and originating from the displays ( 2 ) to the outer sides.

FIELD OF THE INVENTION

The present invention relates to a device, and also relates to adisplay, to an extension, to a method and to a processor programproduct.

Examples of such a device are television sets, display monitors, PCs andlaptops and other consumer devices. An example of such a display monitoris an electronic ink display, a plasma display, a liquid crystal displayor a light emitting diode display.

BACKGROUND ART

European Patent EP 0 572 182 B1 discloses a display unit with anintegral optical input apparatus. The display unit has a liquid crystaldisplay panel comprising conductors in X-axis and Y-axis directionsdisposed on one of the substrates of the panel. These conductors areoptical wave-guides for guiding light parallel to the surfaces of thesubstrates. A light-receiving element for sensing an optical signal isdisposed in an end portion of each of the optical wave-guides.

When light emitted from an optical pen comes into contact with thesubstrate, X and Y coordinates of the contact portion of the emittedlight are determined by the light receiving elements in the form of,e.g., photo sensors. A problem with the device of EP 0 572 182 B1 isthat the optical wave-guides are formed within the substrate, orsubstrates, of the panel. This makes the display unit difficult andexpensive to manufacture, since the processes used for forming thewave-guide in the substrate are rather complex. Moreover, the fact thatthe wave-guides are formed in the substrate is prejudicial to theflexibility in manufacture of the display unit, since the wave-guidesmust in practice be formed in the substrate at the time of manufactureand thus cannot be added to the display unit after manufacture of thesame.

To solve this problem, the non-pre-published European Patent ApplicationSer. No. 03103492.9 (Attorney docket NL 031105) filed Sep. 22, 2003, for“COORDINATE DETECTION SYSTEM FOR A DISPLAY DEVICE” and herewithincorporated by reference, discloses introducing a light-guiding layerhaving an optical structure arranged to confine a fraction of incidentlight from the display device exterior in the light-guiding layer. Theincident light is generated by a remote input device operable by a userfor interacting with the display. The confined light is transmittedthrough the layer towards light-detecting means for detecting theconfined light and relating the detecting of the confined light to aninput position. This display device detects an input position on ascreen of the display device, the display device being easy tomanufacture and the image quality of the display being affected onlyslightly if at all. Within this context, the expression “input position’should be understood to mean the screen coordinate where userinteraction takes place, e.g., where light emitted by an optical penenters the screen.

SUMMARY OF THE INVENTION

It is an object of the invention, inter alia, to provide a device, whichis relatively advanced. Further objects of the invention are, interalia, to provide a display, an extension, a method and a processorprogram product, which are relatively advanced.

The device according to the invention comprises light detector means fordetecting light and in response generating detection information; alight-guiding layer comprising an outer side for guiding incident lightarriving at the outer side and originating from an input device towardsthe light detector means; and a converter for converting the detectioninformation into further information for taking into account an anglebetween the incident light and a predetermined direction relative to thelayer, e.g., an axis substantially perpendicular to the light-guidinglayer.

Compared to the system in non-pre-published European Patent ApplicationSer. No. 03103492.9, referred to above, a converter has been added. Thisconverter forms, for example, part of a processor system and takes theform of, for example, hardware or software components or is a mixture ofboth. The light-guiding layer guides the incident light towards thelight detector means through internal reflections inside of thelight-guiding layer. The incident light can hit the light-guiding layereither perpendicularly or at an oblique angle unequal to zero. Becauseof the guidance inside the light-guiding layer being based on internalreflections, incident light hitting the light-guiding layer at differentangles of incidence will result in different detection information beinggenerated by the light detector means. The converter converts first(second) detection information into first (second) further informationfor taking into account a first (second) angle between the incidentlight and the predetermined direction, e.g., an axis perpendicular tothe light-guiding layer. This axis corresponds with the light-guidinglayer's normal. As a result, the device according to the invention isrelatively advanced.

An embodiment of the device according to the invention is defined by thelight detector means comprising a first detector at a first side of thelight-guiding layer for generating a first detection signal x₁ and asecond detector at a second side of the light-guiding layer forgenerating a second detection signal x₂, the first and second sidesforming opposite sides. In case of the light-guiding layer being in avertical position, the first detector detects first light arriving viathe light-guiding layer at the lower horizontal side of thelight-guiding layer, and the second detector detects second lightarriving via the light-guiding layer at the upper horizontal side of thelight-guiding layer. Thereto, the first and second detector may eachcomprise two or more sub-detectors. The first detector generates thefirst detection signal x₁ and the second detector generates the seconddetection signal x₂, with the first detection signal x₁ and the seconddetection signal x₂ for example representing distances to for examplethe left vertical side of the light-guiding layer. In case of theincident light arriving via a horizontal plane, which horizontal planeis perpendicular to the light-guiding layer, with the incident light notarriving perpendicular to the light-guiding layer, the first detectionsignal x₁ and the second detection signal x₂ will generally be differentfrom each other.

An embodiment of the device according to the invention is defined by thelight detectors further comprising a third detector at a third side ofthe light-guiding layer for generating a third detection signal y. Incase of the light-guiding layer being in a vertical position, the thirddetector detects third light arriving via the light-guiding layer at aleft or right vertical side of the light-guiding layer. Thereto, thethird detector may comprise two or more sub-detectors. The thirddetector generates the third detection signal y, with the thirddetection signal y for example representing a distance to for examplethe upper horizontal side of the light-guiding layer.

An embodiment of the device according to the invention is defined by thefurther information comprising a location of incidence x, y, wherein xis a function of x₁, X₂, and y. This function for example definesx=[yx₁+(y−H)x₂]/(2y−H), wherein H equals the height of the light-guidinglayer. Accordingly, x₁, x₂, and y are measured and x can then becalculated. This embodiment allows a one-dimensional correction of thelocation of incidence, which correction may be necessary owing to thefact that there is an angle between the incident light and an axisperpendicular to the light-guiding layer. Alternative equations can bewritten without departing from the scope of this invention.

An embodiment of the device according to the invention is defined by thefurther information comprising an angle of incidence, which angle ofincidence is linearly dependent on α, wherein tan α is a function of x₁,x₂, and y. This function for example defines tan α=(x₂−x_(l))/(2y−H),wherein H equals the height of the light-guiding layer. So, x₁, x₂, andy are measured and α can then be calculated. This embodiment allows aone-dimensional estimation of a direction of a user location, whichdirection results from the fact that there is an angle between theincident light and an axis perpendicular to the light-guiding layer.Alternative equations can be written without departing from the scope ofthis invention.

An embodiment of the device according to the invention is defined by thelight detectors comprising a third detector at a third side of thelight-guiding layer for generating a third detection signal y₁ and afourth detector at a fourth side of the light-guiding layer forgenerating a fourth detection signal y₂, which third and fourth sidesare opposite sides. In case of the light-guiding layer being in avertical position, the third detector detects third light arriving viathe light-guiding layer at the left vertical side of the light-guidinglayer, and the fourth detector detects fourth light arriving via thelight-guiding layer at the right vertical side of the light-guidinglayer. Thereto, the third and fourth detector may each comprise two ormore sub-detectors. The third detector generates the third detectionsignal y₁ and the fourth detector generates the fourth detection signaly₂, with the third detection signal y₁ and the fourth detection signaly₂ for example representing distances to for example the upperhorizontal side of the light-guiding layer. In case of the incidentlight arriving via a vertical plane, which vertical plane isperpendicular to the light-guiding layer, with the incident light notarriving perpendicular to the light-guiding layer, the third detectionsignal y₁ and the fourth detection signal y₂ will generally be differentfrom each other.

An embodiment of the device according to the invention is defined by thefurther information comprising a location of incidence x, y, wherein xand y are functions of x₁, x₂, y₁, and y₂. These functions for exampledefine x=[yx₁+(y−H)x₂]/(2y−H), wherein H equals the height of thelight-guiding layer, and y=[(x−B)y₁+xy₂]/(2x−B), wherein B equals thewidth of the light-guiding layer. So, x₁, x₂, y₁, and y₂ are measuredand x and y can then be calculated. Because x also depends on y and viceversa, additional information is necessary to solve both equations. Thisadditional information can for example be derived from historyinformation and/or from given limitations, such as the fact that x, andy should be within the dimensions of the light-guiding layer. Thisembodiment allows a two-dimensional correction of the location ofincidence, which correction may be necessary owing to the fact thatthere are angles between the incident light and an axis perpendicular tothe light-guiding layer. Alternative equations can be used withoutdeparting from the scope of this invention.

An embodiment of the device according to the invention is defined by thefurther information comprising a first and a second angle of incidence,wherein the first angle of incidence depends linearly on α and thesecond angle of incidence depends linearly on β, tan α and tan β beingfunctions of x₁, x₂, y₁, and y₂. These functions specify, e.g., tanα=(x₂−x₁)/(2y−H), wherein H equals the height of the light-guidinglayer, and tan β=(y₂−y₁)/(2x−B), wherein B equals the width of thelight-guiding layer. So, x₁, x₂, y₁, and y₂ are measured and α and β canthen be calculated. Because α also depends on y and β also depends on x,additional information is necessary to solve both equations. Thisadditional information can be derived, e.g., from history informationand/or from given limitations, such as the fact that the magnitudes of αand β should be within certain limits. This embodiment allows atwo-dimensional estimation of a direction of a user location. Thedirection results from the fact that there are angles between theincident light and an axis perpendicular to the light-guiding layer.Alternative equations can be used without departing from the scope ofthis invention.

An embodiment of the device according to the invention is defined byfurther comprising a display; and the light-guiding layer comprising aninner side for guiding light arriving at the inner side and originatingfrom the display to the outer side. The display provides images to auser, who operates the remote input device for interaction with (partsof the) images.

An embodiment of the device according to the invention is defined byfurther comprising an adapter for adapting a device parameter inresponse to the further information. This adapter allows the (automatic)adjustment of audio and/or video parameters in dependence of theangle(s) between the incident light and an axis perpendicular to thelight-guiding layer.

An embodiment of the device according to the invention is defined by thedevice parameter comprising a rotation parameter defining a rotation ofa 3D object displayed on a display or a zooming parameter or a scrollingparameter or a volume parameter or a contrast parameter or a brightnessparameter or a sound optimizing parameter. These audio and/or videoparameters are preferably to be adjusted automatically.

An embodiment of the device according to the invention is defined byfurther comprising a selector for selecting, in response to the furtherinformation, a user from a plurality of users each one operating his/herown input device. This selector allows the (automatic) selection ofusers in dependence of the angle(s) between the incident light and anaxis perpendicular to the light-guiding layer, for example to control agame to be played via the display device or for example to individualizeuser settings.

Embodiments of the display according to the invention and of theextension according to the invention and of the method according to theinvention and of the processor program product according to theinvention correspond with the embodiments of the device according to theinvention. As for the processor program product in the invention, thisprogram product is for use on a data processing system, e.g., a homenetwork or a PC or an interactive TV. The system comprises lightdetector means for detecting light and in response generating detectioninformation, and a light-guiding layer that has an outer side forguiding incident light arriving at the outer side and originating froman input device towards the light detectors. The processor programproduct comprises converter means to convert the detection informationinto further information for taking into account an angle between theincident light and a predetermined direction relative to thelight-guiding layer, e.g., an axis substantially perpendicular to thelight-guiding layer. For clarity, the expression “processor programproduct” is meant to cover control software, e.g., on a physical carrieror made available via a data network, that is to be run on a dataprocessor in order to implement the functionality indicated. Suchproduct may be an after-market add-on supplied by the manufacturer ofthe device specified above.

The invention is based upon an insight, inter alia, that the guidanceinside the light-guiding layer is based on internal reflections, wherebyincident light hitting the light-guiding layer at different angles ofincidence results in the light detectors generating different detectioninformation, and is based upon a basic idea, inter alia, that aconverter should convert first (second) detection information into first(second) further information for taking into account a first (second)angle between the incident light and the axis perpendicular to thelight-guiding layer.

The invention solves the problem, inter alia, to provide a device, whichis relatively advanced, and is advantageous, inter alia, in thatone/two-dimensional corrections of locations of incidence and/orone/two-dimensional estimations of directions of user locations can bemade.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further explained, by way of example and with referenceto the accompanying drawing wherein:

FIG. 1 is a diagram of a device comprising a display according to theinvention or an extension according to the invention;

FIG. 2 is a diagram of a vertical light-guiding layer receiving incidentlight via a horizontal plane, the incident light deviating from thelight-guiding layer's normal through a single angle;

FIG. 3 is a diagram of a vertical light-guiding layer receiving incidentlight via a non-horizontal plane, the incident light deviating from thelight-guiding layer's normal through two angles;

FIG. 4 is a diagram of a device in the invention with the light-guidinglayer shown in cross-section; and

FIG. 5 illustrates the angular shift as a function of an angle ofincidence.

DETAILED EMBODIMENTS

The device 1 according to the invention shown in FIG. 1 comprises adisplay 2 coupled to a display driver 3. The display driver 3 is coupledto a processor system 4 that comprises, e.g., an input interface (notshown) for receiving signals to be displayed and/or aman-machine-interface or MMI (not shown) for generating/manipulatingsignals to be displayed and/or a storage interface (not shown) forstoring signals to be displayed, etc. The device 1 further comprises adisplay extension 11-16 comprising light detectors 11-14. A lightreceiving side of light detectors 11-14 is coupled to, or is locatedclosely to, a light-guiding layer 15. An electrical signal generatingside of light detectors 11-14 is coupled to a converter 16. The lightdetectors 11-14 comprise a first detector 11 at a lower horizontal sideof the light-guiding layer 15, a second detector 12 at an upperhorizontal side of the light-guiding layer 15, a third detector 13 at aleft vertical side of the light-guiding layer 15 and a fourth detector14 at a right vertical side of the light-guiding layer 15. The converter16 is further coupled to the processor system 4, to an adapter 17 and toa selector 18. The adapter 17 and the selector 18 are further coupled tothe processor system 4. The display extension 11-16 may form part of a“display 2 according to the invention”, or may form part, together witha “prior art display 2”, of the “device 1 according to the invention”.

The light-guiding layer 15 is described in greater detail in thenon-pre-published European Patent Application Ser. No. 03103492.9(attorney docket NL 031105), referred to above and herewith incorporatedby reference. Generally, this light-guiding layer 15 comprises an outerside and an inner side for guiding incident light arriving at the outerside and originating from an input device towards the light detectors11-14, and for guiding light arriving at the inner side and originatingfrom the display 2 to the outer side to allow a user to watch an imageon the display 2.

The vertical light-guiding layer 15 in FIG. 2 receives light 21 incidentvia a horizontal plane. The incident light 21 deviates from thelight-guiding layer's normal through a single angle. As a result, therespective light detectors 11, 12, and 13 generate the respectivedetection signals x₁, x₂, and y, instead of the respective detectionsignals x, x, and y. The first detection signal x₁ and the seconddetection signal x₂ represent, for example, distances to, e.g., the leftvertical side of the light-guiding layer 15. In case of the incidentlight 21 arriving via a horizontal plane perpendicular to thelight-guiding layer 15, and with the incident light 21 not arrivingperpendicular to the light-guiding layer 15, the first detection signalx₁ and the second detection signal x₂ will generally be different fromeach other. The third detection signal y represents, for example, adistance to e.g., the upper horizontal side of the light-guiding layer15.

The converter 16 in FIG. 1 receives this detection information x₁, x₂,and y and converts it into further information for taking into accountthe angle between the incident light 21 and an axis perpendicular to thelight-guiding layer 15. This further information may, for example,comprise coordinates of a location of incidence x and y, wherein xdepends on x₁, x₂, and y. This dependence specifies x for example asx=[yx1+(y−H)x₂]/(2y−H), wherein H equals the height of the light-guidinglayer 15. So, x₁,x₂, and y are measured and x can then be calculated.This embodiment allows a one-dimensional correction of the location ofincidence. This correction may be necessary owing to the fact that thereis an angle between the incident light 21 and the axis perpendicular tothe light-guiding layer 15. Alternative dependences can be used withoutdeparting from the scope of this invention. This location of incidencehaving an improved accuracy is then supplied from the converter 16 tothe processor system 4, etc.

The further information may alternatively comprise an angle ofincidence. This angle of incidence depends linearly on the angle α,wherein tan α is a function of x₁, X₂, and y. For example, this functiondefines tan α=(x₂−x₁)/(2y−I−), wherein H equals the height of thelight-guiding layer. So, x₁, x₂, and y are measured and α can then becalculated. This embodiment allows a one-dimensional estimation of adirection of a user location. The direction results from the fact thatthere is an angle between the incident light 21 and an axisperpendicular to the light-guiding layer 15. Alternative functions canbe used without departing from the scope of this invention. This angleof incidence is then supplied from the converter 16 to the adapter 17and/or the selector 18 as is further discussed below.

The vertical light-guiding layer 15 in FIG. 3 receives incident light 21via a non-horizontal plane. The incident light 21 deviates from thelight-guiding layer's normal through a first and a second angle. Thefirst angle is situated in a horizontal plane, and the second angle isformed by the angle between this horizontal plane and the non-horizontalplane. As a result, the respective light detectors 11, 12, 13, 14generate the respective detection signals x₁, x₂, y₁, and y₂, instead ofthe respective detection signals x, x, y, and y. The third detectionsignal y₁ and the fourth detection signal y₂ represent, for example,distances to the upper horizontal side of the light-guiding layer 15. Incase of the incident light 21 arriving via a vertical planeperpendicular to the light-guiding layer 15, and with the incident light21 not arriving perpendicular to the light-guiding layer 15, the thirddetection signal y₁ and the fourth detection signal y₂ will generally bedifferent from each other.

The converter 16 in FIG. 1 receives this detection information x₁, x₂,y₁, and y₂ and converts it into further information for taking intoaccount the angles between the incident light 21 and an axisperpendicular to the light-guiding layer 15. This further informationmay, for example, comprise coordinates of a location of incidence x andy, wherein x and y are functions of x₁, x₂, y₁, and y₂. These functionsare, for example, x=[yx₁+(y−H)x₂]/(2y−H), wherein H equals the height ofthe light-guiding layer, and y=[(x−B)y₁+xy₂]/(2x−B), wherein B equalsthe width of the light-guiding layer. So, x₁, x₂, y₁, and y₂ aremeasured and x and y can then be calculated. Because x also depends on yand vice versa, additional information is necessary to solve bothequations. This additional information can, for example, be derived fromhistory information and/or from given limitations, such as the fact thatx and y should be within the dimensions of the light-guiding layer. Thisembodiment allows a two-dimensional correction of the location ofincidence. The correction may be necessary owing to the fact that thereare angles between the incident light and an axis perpendicular to thelight-guiding layer. Alternative equations can be used without departingfrom the scope of this invention. This location of incidence, having animproved accuracy, is then supplied from the converter 16 to theprocessor system 4, etc.

The further information may alternatively comprise a first and a secondangle of incidence. The first angle of incidence depends linearly on theangle α and the second angle of incidence depends linearly on angle β,wherein tan α and tan β are functions of x₁,x₂,y₁,y₂. These functionsare, e.g., tan α=(x₂−x₁)/(2y−H), wherein H equals the height of thelight-guiding layer, and tan β=(y₂−y₁)/(2x−B), wherein B equals thewidth of the light-guiding layer. So, x₁,x₂, y₁,y₂ are measured and αand β can then be calculated. Because α also depends on y and β alsodepends on x, additional information is necessary to solve bothequations. This additional information can be derived, e.g., fromhistory information and/or from given limitations, such as the fact thatα, β should be within certain limits. This embodiment allows atwo-dimensional estimation of a direction of a user location. Thedirection results from the fact that there are angles between theincident light and an axis perpendicular to the light-guiding layer.Alternative equations can be used without departing from the scope ofthis invention. These angles of incidence are then supplied from theconverter 16 to the adapter 17 and/or the selector 18 as furtherdiscussed below.

The adapter 17 adapts a device parameter in response to the furtherinformation comprising one or more angles of incidence. This allows the(automatic) adjustment of audio and/or video parameters in dependence onthe angle(s) between the incident light 21 and an axis perpendicular tothe light-guiding layer 15. Such a device parameter may comprise arotation parameter defining a rotation of a 3D object displayed on thedisplay or a zooming parameter, a scrolling parameter, a volumeparameter, a contrast parameter, a brightness parameter or a soundoptimizing parameter, etc. Accordingly, a user watching the display andoperating the input device at one or more angles of incidenceautomatically gets a 3D object rotated in his/her direction, and/or getsautomatically more or less zooming, more or less scrolling, more or lessvolume, more or less contrast, more or less brightness, and/or adaptedsound, etc.

In response to the further information comprising one or more angles ofincidence, the selector 18 selects a user from a plurality of users eachone operating his/her own input device. this allows the (automatic)selection of users in dependence on the angle(s) between the incidentlight 21 and an axis perpendicular to the light-guiding layer 15, forexample to control a game to be played via the device 1, or toindividualize user settings.

Alternatively, the converter 16 may form part of the processor system 4,for example in the form of hardware or software or a mixture of both;the adapter 17 and/or the selector 18 may form part of the processorsystem 4, for example in the form of hardware or software or a mixtureof both; and the adapter 17 and/or the selector 18 may form part of theconverter 16 for example in the form of hardware or software or amixture of both.

The device 1 of the invention in FIG. 4, the light-guiding layer 15 alsobeing shown in cross-section, further comprises an input device 20 forgenerating the incident light 21. The first detector 11 and the thirddetector 13 are coupled to the converter 16.

The angular shift α, β as a function of the angle of incidence is shownin FIG. 5. Clearly, a linear relationship is present.

Other (remotely controlled) devices with or without a display are not tobe excluded, such as, for example, audio tuners, audio amplifiers,audio/video players/recorders and audio speakers that can individuallybe controlled.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. In the claims, any reference signsplaced between parentheses shall not be construed as limiting the claim.Use of the verb “to comprise” and its conjugations does not exclude thepresence of elements or steps other than those stated in a claim. Thearticle “a” or “an” preceding an element does not exclude the presenceof a plurality of such elements. The invention may be implemented bymeans of hardware comprising several distinct elements, and by means ofa suitably programmed computer. In the device claim enumerating severalmeans, several of these means may be embodied by one and the same itemof hardware. The mere fact that certain measures are recited in mutuallydifferent dependent claims does not indicate that a combination of thesemeasures cannot be used to advantage.

1. A device (1) comprising: light detector means (11-14) for detectinglight and in response generating detection information; a light-guidinglayer (15) comprising an outer side for guiding incident light (21)arriving at the outer side and originating from an input device (20)towards the light detector means (11-14); and a converter (16) forconverting the detection information into further information for takinginto account an angle between the incident light (21) and apredetermined direction relative to the light-guiding layer (15).
 2. Thedevice (1) of claim 1, wherein the light detector means (11-14)comprises a first detector (11) at a first side of the light-guidinglayer (15) for generating a first detection signal x₁ and a seconddetector (12) at a second side of the light-guiding layer (15) forgenerating a second detection signal x₂, and wherein the first andsecond sides are opposite sides of the layer.
 3. The device (1) of claim2, the light detectors (11-14) further comprising a third detector (13)at a third side of the light-guiding layer (15) for generating a thirddetection signal y.
 4. The device (1) of claim 3, the furtherinformation comprising at least one of coordinates of a location ofincidence x, y, wherein x is a function of x₁, x₂, and y.
 5. The device(1) of claim 3, the further information comprising an angle of incidencethat depends linearly on α, wherein tan α is a function of x₁, x₂, andy.
 6. The device (1) of claim 2, wherein the light detectors (11-14)comprise a third detector (13) at a third side of the light-guidinglayer (15) for generating a third detection signal y₁ and a fourthdetector (14) at a fourth side of the light-guiding layer (15) forgenerating a fourth detection signal y₂, the third and fourth sidesbeing opposite sides.
 7. The device (1) of claim 6, wherein the furtherinformation comprises at least one of coordinates of a location ofincidence x, y, wherein x and y are functions of x₁, x₂, y₁, and y₂. 8.The device (1) of claim 6, wherein the further information comprises atleast one of a first angle of incidence and a second angle of incidence,the first angle of incidence depending linearly on α and the secondangle of incidence depending linearly on β, wherein tan αand tan β arefunctions of x₁, x₂, y₁, and y₂.
 9. The device (1) of claim 1, furthercomprising a display monitor (2), and wherein the light-guiding layer(15) comprises an inner side for guiding light arriving at the innerside and originating from the display monitor (2) to the outer side. 10.The device (1) of claim 1, further comprising an adapter (17) for, inresponse to the further information, adapting a device parameter. 11.The device (1) of claim 10, wherein the device parameter comprises atleast one of: a rotation parameter defining a rotation of a 3D objectdisplayed on a display monitor (2); a zooming parameter; a scrollingparameter; a sound volume parameter; an image contrast parameter; animage brightness parameter; a sound optimizing parameter.
 12. The device(1) of claim 1, further comprising a selector (18) for, in response tothe further information; selecting a user from a plurality of users eachone operating his/her own input device (20).
 13. A display monitor (2)comprising a light detector means (11-14) for detecting light and inresponse generating detection information; a light-guiding layer (15)comprising an outer side and an inner side for guiding incident light(21) arriving at the outer side and originating from an input device(20) towards the light detector means (11-14) and for guiding lightarriving at the inner side and originating from the display monitor (2)to the outer side; and a converter (16) for converting the detectioninformation into further information for taking into account an anglebetween the incident light (21) and an axis substantially perpendicularto the light-guiding layer (15).
 14. An extension (11-16) comprisinglight detector means (11-14) for detecting light and in responsegenerating detection information; a light-guiding layer (15) comprisingan outer side for guiding incident light (21) arriving at the outer sideand originating from an input device (20) towards the light detectormeans (11-14); and a converter (16) for converting the detectioninformation into further information for taking into account an anglebetween the incident light (21) and a predetermined direction relativeto the light-guiding layer (15).
 15. A method for use with lightdetector means (11-14) for detecting light and in response generatingdetection information, and with a light-guiding layer (15) comprising anouter side for guiding incident light (21) arriving at the outer sideand originating from an input device (20) towards the light detectors(11-14), the method comprising converting the detection information intofurther information for taking into account an angle between theincident light (21) and a predetermined direction relative to thelight-guiding layer (15).
 16. A processor program product for use on adata processing system, the system comprising light detector means(11-14) for detecting light and in response generating detectioninformation; and a light-guiding layer (15) that has an outer side forguiding incident light (21) arriving at the outer side and originatingfrom an input device (20) towards the light detectors (11-14), whereinthe processor program product comprises converter means to convert thedetection information into further information for taking into accountan angle between the incident light (21) and a predetermined directionrelative to the light-guiding layer (15).